Which statement provides evidence for the active loading of sucrose into companion cells?
- AThe pH decreases in the cell wall of the companion cells compared to the cytoplasm.
- BThe pH decreases in the cytoplasm of the companion cells compared to the cell wall.
- CThe pH decreases in the plasmodesmata between companion cells and sieve tube elements.
- DThe pH decreases in the sieve tube elements compared to the companion cells.